1. Field of the Invention
The present invention relates to a power output apparatus and an automobile with the power output apparatus mounted thereon.
2. Description of the Prior Art
One proposed power output apparatus includes a planetary gear unit linked with an output shaft of an internal combustion engine, a rotational shaft of an electric generator, and a drive shaft as a rotational shaft of an electric motor, as well as a brake mechanism that stops rotation of the rotational shaft of the electric generator (for example, JAPANESE PATENT LAID-OPEN GAZETTE No. 9-117010). In this power output apparatus, the power output from the internal combustion engine and input into a carrier of the planetary gear unit is partly output to the drive shaft connecting with a ring gear of the planetary gear unit by application of a reaction force by means of the electric generator connecting with a sun gear of the planetary gear unit. The residual power is taken out as electric power, which is utilized for torque output from the electric motor to the drive shaft. Under such control, the power of the internal combustion engine driven at a drive point of high efficiency is subjected to torque conversion and is output to the drive shaft. The brake mechanism stops the rotation of the electric generator according to the requirements, thus reducing the energy loss due to the electric generator and enhancing the total energy efficiency of the whole power output apparatus.
This prior art power output apparatus, however, can not reduce the energy loss due to the electric motor, while activating the brake mechanism to stop the rotation of the electric generator and reduce the energy loss due to the electric generator. In the case where the brake mechanism functions to stop the rotation of the electric generator, the sun gear of the planetary gear unit is fixed. This prevents the drive point of the internal combustion engine from being set freely and may cause the internal combustion engine to be driven in a driving area of rather poor efficiency. One possible measure against this problem stops the rotation of the electric generator by means of the brake mechanism only under the condition that the internal combustion engine is in a driving area of high efficiency. This method, however, reduces the chance of stopping the rotation of the electric generator and thereby decreases the chance of enhancing the total energy efficiency of the power output apparatus.
The object of the present invention is thus to enhance the total energy efficiency of a power output apparatus and a vehicle with the power output apparatus mounted thereon.
In order to achieve at least a part of the aforementioned objects, the power output apparatus and automobile with power output apparatus mounted thereon of the present invention is structured as follows.
A power output apparatus of the present invention is a power output apparatus that outputs power to a drive shaft, the power output apparatus including: an internal combustion engine; a drive shaft electric motor that is mechanically linked with the drive shaft and inputs and outputs power into and from the drive shaft; a triaxial power input output module that is connected to three shafts, that is, an output shaft of the internal combustion engine, the drive shaft, and a rotational shaft and, when powers input into and output from any two shafts among the three shafts are specified, determines power input into and output from a residual shaft, based on the specified powers; a rotational shaft electric motor that inputs and outputs power into and from the rotational shaft; a rotation stop module that fixes the rotational shaft to stop rotation of the rotational shaft; and an electric motor connecting and releasing module that mechanically connects the drive shaft with the drive shaft electric motor and releases the mechanical connection of the drive shaft with the drive shaft electric motor.
In the power output apparatus of the present invention, when the rotation stop module is not activated and the electric motor connecting and releasing module functions to mechanically connect the drive shaft with the drive shaft electric motor, the power of the internal combustion engine is subjected to torque conversion by the triaxial power input output module, the drive shaft electric motor, and the rotational shaft electric motor, and is output to the drive shaft. Under such conditions, when the rotation stop module is activated to fix the rotational shaft and stop rotation of the rotational shaft, the power of the internal combustion engine is directly output to the drive shaft. In this state, the rotational shaft electric motor is stopped, so that energy loss of the rotational shaft electric motor is decreased to zero. When the electric motor connecting and releasing module functions to release the mechanical connection of the drive shaft with the drive shaft electric motor, the drive shaft electric motor is also stopped. This decreases the energy loss of the drive shaft electric motor to zero. The arrangement of the present invention thus effectively enhances the total energy efficiency of the whole power output apparatus.
Further, in the power output apparatus of the present invention structured in this way, there may be provide with a controller that controls the rotation stop module to stop the rotation of the rotational shaft and controls the electric motor connecting and releasing module to release the mechanical connection of the drive shaft with the drive shaft electric motor, when a predetermined rotation stop condition is fulfilled. Moreover, in the power output apparatus of the present invention, there may be provided with a controller that controls the rotation stop module to cancel the stop of the rotation of the rotational shaft and controls the electric motor connecting and releasing module to mechanically connect the drive shaft with the drive shaft electric motor, when a predetermined stop cancellation condition is fulfilled. In one preferable embodiment of these applications, the power output apparatus is further provided with a revolving speed sensor that measures a revolving speed of the drive shaft. The predetermined rotation stop condition is that the revolving speed of the drive shaft measured by the revolving speed sensor is not less than a first changeover revolving speed. The predetermined stop cancellation condition is that the revolving speed of the drive shaft measured by the revolving speed sensor is not greater than a second changeover revolving speed.
Moreover, in the power output apparatus of the present invention, there may be provided with a revolving speed sensor that measures a revolving speed of the drive shaft; and
a controller that controls the rotation stop module to stop the rotation of the rotational shaft and controls the electric motor connecting and releasing module to release the mechanical connection of the drive shaft with the drive shaft electric motor, when a first changeover condition is fulfilled where the revolving speed of the drive shaft measured by the revolving speed sensor is over a preset changeover revolving speed range,
the controller controlling the rotation stop module to cancel the stop of the rotation of the rotational shaft and controlling the electric motor connecting and releasing module to mechanically connect the drive shaft with the drive shaft electric motor, when a second changeover condition is fulfilled where the revolving speed of the drive shaft measured by the revolving speed sensor is below the preset changeover revolving speed range. In this case, the triaxial power input output module may be regulated to make a revolving speed of the rotational shaft within a predetermined revolving speed range including a value xe2x80x980xe2x80x99, when the drive shaft is rotated in the preset changeover revolving speed range against a general required power, the internal combustion engine is driven to enable a power corresponding to the general required power to be efficiently output from the internal combustion engine, and the rotational shaft electric motor and the drive shaft electric motor are driven to output the general required power to the drive shaft. Further, the triaxial power input output module may be regulated to enable the internal combustion engine to be driven in a predetermined driving area of high efficiency, when the drive shaft is rotated in the preset changeover revolving speed range against a general required power, and the rotational shaft electric motor and the drive shaft electric motor are driven in order to cause a power corresponding to the general required power output from the internal combustion engine to be transmitted to the drive shaft as the general required power and in order to rotate the rotational shaft within a predetermined revolving speed range including a value xe2x80x980xe2x80x99.
Further, in the power output apparatus of the present invention, there may be provided with a transmission that is interposed between the drive shaft electric motor and the drive shaft to change an input revolving speed and output a resulting revolving speed.
An automobile of the present invention is an automobile, including:
an internal combustion engine;
a drive shaft electric motor that is mechanically linked with a drive shaft, which is connected to an axle, and inputs and outputs power into and from the drive shaft;
a triaxial power input output module that is connected to three shafts, that is, an output shaft of the internal combustion engine, the drive shaft, and a rotational shaft and, when powers input into and output from any two shafts among the three shafts are specified, determines power input into and output from a residual shaft, based on the specified powers;
a rotational shaft electric motor that inputs and outputs power into and from the rotational shaft;
a rotation stop module that fixes the rotational shaft to stop rotation of the rotational shaft;
an electric motor connecting and releasing module that mechanically connects the drive shaft with the drive shaft electric motor and releases the mechanical connection of the drive shaft with the drive shaft electric motor;
a vehicle speed sensor that measures a vehicle speed; and
a controller that controls the rotation stop module to stop the rotation of the rotational shaft and controls the electric motor connecting and releasing module to release the mechanical connection of the drive shaft with the drive shaft electric motor, when a first changeover condition is fulfilled where the vehicle speed measured by the vehicle speed sensor is over a preset changeover vehicle speed range,
the controller controlling the rotation stop module to cancel the stop of the rotation of the rotational shaft and controlling the electric motor connecting and releasing module to mechanically connect the drive shaft with the drive shaft electric motor, when a second changeover condition is fulfilled where the vehicle speed measured by the vehicle speed sensor is below the preset changeover vehicle speed range.
In the automobile of the present invention, when the rotation stop module is not activated and the electric motor connecting and releasing module functions to mechanically connect the drive shaft with the drive shaft electric motor, the power of the internal combustion engine is subjected to torque conversion by the triaxial power input output module, the drive shaft electric motor, and the rotational shaft electric motor, and is output to the drive shaft connecting with the axle. Under such conditions, when the rotation stop module is activated to fix the rotational shaft and stop rotation of the rotational shaft, the power of the internal combustion engine is directly output to the drive shaft. In this state, the rotational shaft electric motor is stopped, so that energy loss of the rotational shaft electric motor is decreased to zero. In the automobile of the present invention, the controller controls the rotation stop module to stop the rotation of the rotational shaft and controls the electric motor connecting and releasing module to release the mechanical connection of the drive shaft with the drive shaft electric motor, when a first changeover condition is fulfilled where the observed vehicle speed is over a preset changeover vehicle speed range. This results in inducing direct output of the power from the internal combustion engine to the drive shaft. The controller controls the rotation stop module to cancel the stop of the rotation of the rotational shaft and controls the electric motor connecting and releasing module to mechanically connect the drive shaft with the drive shaft electric motor, when a second changeover condition is fulfilled where the observed vehicle speed is below the preset changeover vehicle speed range. This results in canceling the direct output of the power from the internal combustion engine to the drive shaft. The arrangement of the invention thus effectively enhances the total energy efficiency of the automobile according to the vehicle speed.
In the automobile of the present invention, the triaxial power input output module may be regulated to make a revolving speed of the rotational shaft within a predetermined revolving speed range including a value xe2x80x980xe2x80x99 when the drive shaft is rotated in the preset changeover revolving speed range against a general required power, the internal combustion engine is driven to enable a power corresponding to the general required power to be efficiently output from the internal combustion engine, and the rotational shaft electric motor and the drive shaft electric motor are driven to output the general required power to the drive shaft. Further, the triaxial power input output module may be regulated to enable the internal combustion engine to be driven in a predetermined driving area of high efficiency, when the drive shaft is rotated in the preset changeover revolving speed range against a general required power, and the rotational shaft electric motor and the drive shaft electric motor are driven in order to cause a power corresponding to the general required power output from the internal combustion engine to be transmitted to the drive shaft as the general required power and in order to rotate the rotational shaft within a predetermined revolving speed range including a value xe2x80x980xe2x80x99.
In one preferable application of the present invention, the automobile is further provided with a transmission that is interposed between the drive shaft electric motor and the drive shaft to change an input revolving speed and output a resulting revolving speed.